CLASSICAL AND QUANTUM LAWS 195 



strong confidence. Better admit that there was some 

 truth both in science and religion; and if they must fight, 

 let it be elsewhere than in the brain of a hard-working 

 scientist. If we have ever scorned this attitude, Nemesis 

 has overtaken us. For ten years we have had to divide 

 modern science into two compartments; we have one set 

 of beliefs in the classical compartment and another set 

 of beliefs in the quantum compartment. Unfortunately 

 our compartments are not watertight. 



We must, of course, look forward to an ultimate 

 reconstruction of our conceptions of the physical world 

 which will embrace both the classical laws and the 

 quantum laws in harmonious association. There are still 

 some who think that the reconciliation will be effected 

 by a development of classical conceptions. But the 

 physicists of what I may call "the Copenhagen school" 

 believe that the reconstruction has to start at the other 

 end, and that in the quantum phenomena we are getting 

 down to a more intimate contact with Nature's way of 

 working than in the coarse-grained experience which 

 has furnished the classical laws. The classical school 

 having become convinced of the existence of these uni- 

 form lumps of action, speculates on the manufacture of 

 the chopper necessary to carve off uniform lumps; the 

 Copenhagen school on the other hand sees in these 

 phenomena the insubstantial pageant of space, time and 

 matter crumbling into grains of action. I do not think 

 that the Copenhagen school has been mainly influenced 

 by the immense difficulty of constructing a satisfactory 

 chopper out of classical material; its view arises espe- 

 cially from a study of the meeting point of quantum and 

 classical laws. 



The classical laws are the limit to which the quantum 

 laws tend when states of very high quantum number are 

 concerned. 



